(1) Field of the Invention
The present invention relates to a liquid crystal display and a backlight controller (i.e., a dimmer) thereof, and it relates, in particular, to a liquid crystal display and a backlight controller thereof, for enabling to adjust or control brightness of the backlight, depending upon the characteristics or features of an image to be displayed on that display.
(2) Description of the Related Arts
In recent years, because of the thin thickness thereof, the liquid crystal display is widely adopted, as a flat-type display device for displaying an image thereon, such as, for use in a television receiver, or a display device for a computer, as well as, a plasma display panel (PDP).
In particular, within the liquid crystal display for use of displaying the image on a screen, which is made of a liquid crystal display panel, there is provided a backlight for illuminating or lighting up that liquid crystal display from the rear surface thereof. And, normally, an operator adjusts or controls brightness of this backlight, by adjusting or controlling a controller device for the backlight, variably, and thereby obtaining a clear or easy screen to see.
However, in such the case, as is disclosed in Japanese Patent Laying-Open No. Hei 8-201812 (1996), for maintaining the brightness of display and also the contract of the liquid crystal display device to be almost constant, irrespective of changes of the an averaged level of video signals and the temperature of the backlight, it is already known to detect the averaged level of video signals by an APL detector circuit, wherein the brightness of the backlight is decreased if the averaged level of video signals by the APL detector circuit is high, while the brightness of the backlight is increased if the averaged level of video signals by the APL detector circuit is low.
Also, for determining the brightness of liquid crystal panel to be most suitable or appropriate for a screen to be seen, for example, in Japanese Patent Laying-Open No. 2005-308792 (2005), it is also already known to calculate out an averaged value “Ave” of brightness from the video signals obtained during a predetermined time-period, with an aid of a microcomputer, and thereby reducing the brightness of illumination of the backlight when the averaged value of that brightness exceeds or higher than a predetermine threshold value, while increasing the brightness of illumination of the backlight when the averaged value of that brightness is lower than that predetermine threshold value.